Drawbench



Jan. 23, 1945;

E. J. M ILVRIED ETAL DRAW BENCH Filed Jan. 1, 1942 6 Sheets-Sheet 1 INVENTORS EDWINJ.McILVRlEDOnd NORMAN H.NYE

BY 060110, ATTORNEYS .Pan. 23, 1945.

E. J. MCILVRIED ETAL DRAW BENCH Filed Jan. 1, 1942 6 Sheets-Sheet 2 INVENTORS EDWIN J.MclLVRIEDOnd NORMAN H.NYE

BY m l F .0 ATTORNEYS Jan 23, 1945.

E. J. M lLVRlED ETAL.

DRAW BENCH 6 Sheets-Sheet 3 Filed Jan. 1, 1942 INVENTORS gowm J. MclLVRIEDond BY NORMANHNYE Jan. 23, 1945.

E. J. MCILVRIED ETAL DRAW BENCH 6 Sheets-Shed 4 Filed Jan. 1, 1942 W H IHL M on H m QM R W W I UT; m H A J N mm WR Dm.

Mia/L 1945; E. J. MCILVRIED ETAL 2,367,793

DRAW BENCH Filed Jan. 1, 1942 6 Sheets-Sheet 5 II JO I A m I5 -15 16 A IS an LED EE. 9 INVENTORS EDWIN J.MCILVRIED and NORMAN H. NYE.

M WiQ ATTORNEYS Jan. 23, 1945. E. J. MCILVRIED ETAL 2,367,793

DRAW BENCH Filed Jan. 1, 1942 6 Sheets-Sheet 6 40 I J 32I G 0 34 45 I o g 331.: 1-: 1: i\:;:: IE" i 19) 8 8612 60 so: 12' 5| 5] I 3 I I Q 4 2e 0 0 26 o 2 8 22 I6 INVENTORS EDWIN J.MclLVR|EDond NORMAN H.NYE

ATTORNEYS A latented 23, 1945 2,367,793 naswnancn Edwin J. Mcllvrled, Akron, and Norman n. Nye,

Cuyahoga Falls, Ohio, asslgnors to The Vaughn Machinery Company, Cuyahoga Falls, Ohio, a corporation of Ohio Application January 1, 1942, Serial No. 425,358

(Cl. 2il5-3) 29 Claims.

This invention relates as indicated to draw benches, and more particularly to drawing mechanism especially adapted to the drawing of tubes and the like.

In the past, drawing mechanism of this type has been relatively slow in operation and particularly in the steps of removing the work pieces from the bench after completion of the drawing operation and the return of the work gripping means to the die end of the bench to seize and draw further work. In one type of draw bench commonly employed, such work gripping means is connected to an endless chain and such means is reciprocated along the bench by reversing the direction of movement of such chain as by the employment of a reversing motor or the like. Or the work gripping means may be releasably attached to the endless chain and additional means provided for returning the work gripping means to the die end of the bench. The work in process of being drawn has generally been supported upon subjacent means from which the work must be lifted subsequent to the drawing operation. As the latter end of such work passes through and is released from the die, there has been a strong tendency for such work to whip or snap with possible resultant injury to the work, operator or machine.

It is therefore a primary object of this invention to provide an improved drawing mechanism in which the work gripping means is automatically. closed to seize the work and automatically opened to release the work.

Another object of this invention is to .provide means connecting such gripper means to the usual endless chain or cable whereby such gripper means may be reciprocated in a rectilinear path without the necessity of reversing the direction of movement of such endless chain.

A further object is to provide supporting means for the drawing mechanism which will permit discharge of the work pieces to one side of the draw bench upon completion of the drawing operation, even when two or more draw benches are in operation side-by-side and supported by the same supporting means.

A further object is to provide means automatically operative to frictionally grasp the work pieces shortly prior to passage of the latter ends thereof through the dies to prevent whipping of such ends upon release from the dies.

A further object is to provide means associated with the driving means for ensuring tight engagement of such driving means with the endless chain to which the work gripping means is attached.

Other objects of this invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following descriptlon set forth in detail certain mechanism embodying thelnvention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings:

Fig. 1 is a top plan view of the die end of a double draw bench constructed in accordance with our invention;

Fig. 2 i a side elevational view of the die end of such draw bench;

Fig. 3 is a. side elevatlonal view of the drive end of such draw bench; V

Fig. 4 is a diagrammatic lay-out of the-electric control and valve means for operating the double acting cylinders which close and open the tube clamping means;

Fig. 5 is a sectional view in elevation of the drive end of the draw bench;

Fig. 6 is a side elevational view of the work gripping means with a portion broken away to show the inner mechanism;

Fig. 7 is a view similar to Fig. 6 but showing the Jaws in open position;

Fig. 8 is a top detail view of the jaw mechanism with the upper portion of the enclosing carriage broken away;

Fig. 9 is a sectional view taken along the line 9--9 on Fig. 6;

Fig. 10 is a detail view showing the manner in which the gripper means is attached to the end less chain;

Fig. 11 is a sectional view taken transversely of the draw bench adjacent the die end of the machine; and

Fig. 12 is a transverse sectional view of the draw bench showing the work gripping means mounted thereon.

Referring now more particularly to said drawings, the mechanism of this invention is. supported by a series of substantially c-shaped base members I with the exception of the drive end of the machine which is supported on a box frame 2. Suspended from'the upper or bracket portions of such c-shaped members are two parallel longitudinal guideways 3 and 4 bearing trackways 5, 6, 1 and 8.

Since the mechanism supported by and associated with each of said guideways is substantially identical, the one being the mirror image of the other, only the mechanism associated with outer guideway 4 will be described in detail, the parts associated with guideway 3 being given prime numbers corresponding to the numbers accorded the parts associated with guideway 4. At one end of the guideways are die mounts 3 bearing four dies 10 in vertical alignment therein. Slung from trolleys ll, i2 and I3, running on trackways 1 and 8 (or trackways and 8 in the case of the mechanism associated with guideway 3), is a carriage l4 containing upper and lower pairs of jaws l5 and I6 respectively slidably mounted in angularly related camways in such carriage. (See Figs. 6 to 9 inclusive.) Pins 11 and 3 pass transversely through the back portions of such jaw members and are centrally held by an upright member i9 itself pivotally held within yoke member 20. Such yoke member is mounted on the end of rod 2| adapted to be reciprocated back and forth in the casing. Pivotally mounted on the casing at 22 is a bell-crank lever in the end of one arm 23 of which rod 2| is slidably mounted, lock nuts 24 preventing such rod from escaping from the arm. A coil spring 25 is interposed between the end of such arm and yoke 20 so that when the arm is moved forwardly to advance the jaw members in their angularly related cam slots to close the jaws, the tubing or other work pieces seized by the jaws will be firmly but resiliently held. An endless chain 26 is mounted on sprocket 21 adjacent the die end of the bench and on sprocket 28 at the drive end of the bench, the lower course of such chain passing between idlers 29 and 30 shortly before reaching such drive sprocket. An arm 3| of said lever is pivotally attached to said chain, as best shown in Fig. 10, by means of a special bushing 32 so formed that the chain may pass over the sprockets without interference from the lever arm or attaching means. When such lever arm 3| is attached to the lower course of the chain, as shown in Fig. 6, arm 23 will be bearing on spring 25 to effect closure of the gripper jaws. On the other hand, when the point of attachment of lever arm 3i to the chain has been elevated by idler 30 or has passed around sprocket 28 and is therefore on the upper course of the chain, lever arm 23 will have been drawn back, thus opening the gripper jaws, as shown in Fig. 7. It will therefore be seen that as chain 28 moves in the direction indicated by the arrows on Fig. 2, the gripper mechanism will be drawn along the guideway with the jaws in closed position until the point of-attachment of lever arm 3| to the chain passes over idler 30, at which point the gripper jaws will be opened. As such point of attachment passes around drive sprocket 28 from the lower to the upper course of the chain, carriage l4 will be reciprocated along its supporting guideway toward the die end of the bench. When such point of attachment passes about sprocket 21 from the upper to the lower course of the chain, the gripper jaws will of course again be closed. The upper course of the chain is supported on a track carried by bracket 35 on the side of guideway 4, the lower course being supported on a similar track 81 on trolley trackway 8.

Clamping means are provided adjacent the die end of the bench to frictionally grasp the tubing shortly prior to the passage of the latter end thereof through the dies. Such clamping means comprises a pair of arms 32 and 33, the former pivotally and the latter tightly mounted on a shaft 34 journalled in ends of cross members 33 and 36. Toggle links 31 and 38 pivotally link said arms to T-arm 39 pivotally mounted at 40, said toggle arms b'eing adjustable by turnbuckle means to provide for proper adjustment of the clamp. It is apparent, therefore, that outward movement of clamping arm 33 will cause arm 32 to swing in an opposite direction through the action of such toggle means. A double acting air cylinder 4| is carried by an upward extension of cross member 36 and is provided with a piston, an extension 42 of which is pivotally attached to the end of rocker arm 43 which is tightly mounted on shaft 34. It will thus be seen that when fluid pressure, such as air pressure, is admitted to cylinder 41 to move rod 42 outwardly the clamp will be closed, as shown in the right hand clamp in Fig. 11. The clamp .proper comprises a shoe 44 pivotally mounted on arm 32 and another shoe 45 mounted on arm 33 with spring backed plates 48 mounted therein to ensure that the tubing is frictionally held in the four cooperating cut-away portions of the respective shoes adapted to receive'the tubing. As also shown in the left hand clamp in Fig. 11, when air pressure is admitted' to the opposite end of the double acting cylinder the clamp arms are swung apart to permit the gripper carriage l4 to advance therebetween toward the dies to seize new work pieces as the point of attachment of lever arm 3! to the chain passes around sprocket 21.

To close such clamp at the proper time a limit switch 41 is mounted on guideway 4 adjacent the drive end of the bench in proper position to be tripped shortly prior to, the passage of the latter ends of the work pieces through the dies. Trip- 40 ping means for such switch is mounted on an upward extension 43 of gripper carriage i4, such means comprising an upstanding arm 49 journailed in said member 43 for pivotal movement in a vertical plane. On the opposite side of member 48 is mounted a spring backed plunger 50 bearing a yoke member 51, the ends of which are adapted to engage the bevelled shoulders of an extension 52 of said arm 43. Thus when arm 43 engages and trips limit switch 41 such arm will be tipped back against the resilient pressure of plunger 50 and thus enabled to clear the switch as well as being returned to an upright position thereafter.

Upon reciprocation of gripper carriage l4, arm 48 will engage switch 41 on the return journey to open the switch and thereby cause the opening of the clamping means. The limit switch 41 is in an electric circuit including a relay coil 53 and an on-and-ofi button 54 of the maintaining type provided for manual control of the clamping means, if such should be desired. Line 55 is connected to a 220 volt 60 cycle current source. When limit switch 41 is closed during the drawing operation, relay contacts 56 are thereby likewise closed, causing solenoid valve 51 to be operated to admit compressed air to an end of cyliner 41 whereby rod 42 is extended and the clamping means closed. Of course when the limit switch is open the solenoid valve will act to admit compressed air to the other end of the cylinder and the clamp will likewise be open. (See Fig.4.)

In order to obviate any chance of damage to the mechanism due to failure of the electric circuit or for other reason, positive means are provided adapted to open the clamp as the gripper carriage approaches the same so that collision therebetween may be avoided. Such means com- .prises a cam roller 58 mounted on the end of arm 59 locked to shaft 34. A cam track 60 is provided on member 48 adapted to engage said cam roller 58 and raise the same to rock shaft 38 and thus open the clamp. Of course if such clamp has already been opened as will have been the case in normal operation, cam roller 58 will have been raised to a position where it will not engage camway 60.

Journalled in depending arms 6| is a shaft 62 carrying a plurality of rack members 63. At the die end of the bench is a double acting cylinder 64 with a plunger 65 extending from the lower end thereof. Such plunger is connected by means of a link 66 to lever arm 6! locked to the end of shaft 62 so that upon admission of compressed air to respective ends of cylinder 64 shaft 62 may be rocked to elevate or depress rack members 63. Control valve means 68 are provided for manual operation of the rack. As best shown in Fig. 11, similar rack members 69 are mounted on shaft ill below guideway 3 and adapted to be operated by similar link and lever means connected to the plunger of double acting cylinder ll mounted on -C-frame member l. Such last named cylinder is also provided with manual control means, not shown. It will thus be seen that when such cylinders are operated to depress rack members $9 and 63 containing the work pieces dropped thereon by the gripper jaws at the conclusion of the drawing operation, such work pieces will roll down the inclined guideway 12 comprised by the upper surfaces of the base portions of mem bars 5 and be laterally discharged into the receiving rack 13. It will be noted that this construction provides for all of the work pieces from both of the guideways being discharged laterally at the same side of the draw bench. 'This facilitates removal of the completed work and permits a greater degree of access to the bench.

As best shown in Figs. 3 and 5, the driving.

mechanism comprises an electric motor 14 operative to turn a drive shaft 15 to which gears 16 and is are keyed. Mounted for pivotal movement about the axis of such drive shaft are two housings or casings Ti and 11' in which are journalled shafts 1.8 and 18' respectively. Keyed to the outer end of shaft 78 is drive sprocket 28 and keyed to such shaft within housing 11 is gear 19 in driven engagement with said gear 16. It is at once apparent that gears 76 and 19 will maintain proper engagement when housing 11 is rotated about the axis of drive shaft 15. Pivotally mounted on stub shaft 80 in boss 8| of casing .11 is an arm 82 joined by means of a turnbuckle 83 to arm 84 pivotally mounted on guideway 4. It will be seen that by means of tumbuckle 83 housing l'l may be tipped about the axis of drive shaft 15 to ensure tight engagement of sprocket 28 and chain 26, the turnbuckle acting as a jack. Similar means is provided to tighten the chain travelling along guideway 3 on drive sprocket 28', it being noted that gears i9 and 1.9 each have their respective separately adjustable housings.

While the operation of the drawing mechanism of this invention is more or less obvious from the foregoing description, such operation will nevertheless be briefly explained. The ends of the work pieces are inserted in the dies in position to be seized by the jaws of the gripper mechanism,

the feeding or loading means being no part of the work pieces to be drawn. As carriage l4 moves along guideway 4 the work is drawn through the dies. Shortly prior to the passage of the latter ends of the work pieces through the dies, the upstanding arm engages limit switch to cause arms 32 and 33 to swing their respective clamping shoes into cooperative frictional clamping engagement with the work pieces. Buckling and whipping of the work caused by jumping forward as it is released from the die is thus avoided. Otherwise the tubin may be bent into a sinuous configuration seriously interfering with further handling. The work gripping means continues to move along the guideway until the ends of the work pieces clear the aforesaid clamp. Shortly' thereafter the point of attachment of lever arm 3| passes over idler 30 operating to open the work gripping jaws and permit such work to be deposited on rack members 63. Sufficient time is thus afforded for the carriage M to get out of the way of the tube before the point of attachment of lever arm 3| of the chain passes about sprocket 28 causing reciprocation of gripper carriage M in the opposite direction toward the die end of the machine, where the procedure is repeated. Of course the gripper mechanism carried by guideway 3 operates in a similar manner in conjunction with its respective clamping mechanism, likewise operated by a solenoid valve controlled by a limit switch. The limit switches may be adjustabiy located on the guideways to adapt the operation of the clamping means to difierent lengths of tubing.

Although in Figs. 1 and 12 the gripper means of the two guideways' are shown side by side, such gripper means may be oppositely located on their respective guideways so that one will just be seizing work to be drawn when the other has released the completed work and is about to return to the die end. In this way, work will be drawn on only one bench at a time and a less powerful driving means will be required than when both benches are engaged in drawing work simultaneously.

It will be seen from the foregoing thairdrawing mechanism has been provided affording a great economy in the use of power and the operators time. The underslung work gripping means permits the completed work to be deposited on the subjacent racks for lateral discharge, thus avoiding heavy manual labor and speeding operations.

Other modes of applying the principle of our ciprocating movement therealong, means including lever means connecting said gripper 'means to said'chain operative to reciprocate said gripper means along said guideway upon movement of said endless chain in a single direction, said lever means being operative to maintain said gripper means in open position when the point of attachment of said lever means to said chain is travelling with the upper course of said chain and to maintain said gripper means in closed position when such point of attachment is travelling with the lower course of said chain.

2. In drawing mechanism, a guideway, an endless chain supported adjacent said guideway and having upper and lower courses substantially parallel thereto, means for driving said chain, gripper means supported by said guideway for reciprocating movement therealong, means including lever means connecting said gripper means to said chain operative to reciprocate said gripper means along said guideway upon movement of said endless chain in a single direction,

said lever means attached to said chain being operative to close said gripper means when the point of at achment of said lever means to said chain is on the lower course of said chain. and to open said gripper means when such point of attachment is raised above such lower course, and means adjacent an end of such lower course adapted to raise said chain to cause opening of said gripper means shortly before reaching the end of such lower course.

3. In drawing mechanism, 'a guideway, sprockets adjacent each end of said guideway, an endless chain mounted on said sprockets comprising an upper and a lower course, means for driving one of said sprockets to drive said chain, gripper means supported by said guideway for reciprocating movement therealong, means connecting said gripper means to said chain operative to reciprocate said gripper means along said guideway upon movement of said endless chain. in a single direction, said connecting means comprising lever means pivotally attached to said chain and operative to close said gripper means when the point of attachment of said lever means to said chain in on the lower course of said chain and to open said gripper means when such point of attachment is raised above such lower course, and means adjacent said driven sprocket over which said lower course of chain is adapted to pass prior to reaching said driven sprocket operative to raise said chain to open said gripper means upon passing of such point of attachment thereover before reaching the end of such lower course.

4. In drawing mechanism, a guideway, a die through which work is drawn located adjacent one end of said guideway, an endless chain supported adjacent said guideway and having upper and lower courses arranged substantially par allel thereto, means for driving said chain with such lower course moving away from said die, gripper means supported by said guideway for movement therealong and operative'to seize the work and draw such work through said die, means connecting said gripper means to said chain operative to reciprocate said gripper means from and toward said die upon movement of said endless chain in a single direction, said connecting means comprising lever means pivotally attached to said chain and operative to close said gripper means when the point of attachment of said lever means to said chain is on the lower course of said chain and to open said gripper means when such point of attachment is on the upper course of said chain, clamping means located adjacent said die operative to frictionally grasp such work to prevent Ill] jumping of the latter end thereof upon sudden release from said die, air pressure means operative to open and close said clamping means, an electric circuit including a limit switch to control the voperation of said air pressure means, and means travelling with said gripper means operative to engage said limit switch shortly prior to passage of the work through said die to cause closing of said clamping means and to engage said limit switch upon reciprocation of said gripper means toward said die to cause opening of said clamping means.

5. In drawing mechanism, a die through which work isdrawn, gripper means operative to seize the work and draw such work through said die, clamping means located adjacent said die operative to frictionally grasp such work to prevent jumping of the latter end thereof upon sudden release from said die, fluid pressure means operative to open and close said clamping means, a solenoid valve to control said pressure means, an electric circuit including a limit switch to control the action of said valve, and means automatically operative to engage said limit switch to cause closing of said clamping means shortly prior to passage of the latter end of such work through said die. I

6. In drawing mechanism, a guideway, a die through which work is drawn located adjacent one end of said guideway, an endless chain supported adjacent said guideway and having upper and lower courses arranged substantially parallel thereto, means for driving said chain with such lower course moving away from said die, gripper means supported by said guideway for movement therealong and operative to seize the work and draw such work through said die, means connecting said gripper means to said chain operative to reciprocate said gripper means from and toward said die upon movement of said endless chain in a single direction, said connecting means comprising lever means pivotally attached to said chain and operative to close said gripper means when the point of attachment of said lever means to said chain is on the lower course of said chain and to open said gripper means when such point of attachment is on the upper course of such chain, clamping means located adjacent said die operative to frictionally grasp such work to prevent jumping of the latter end thereof upon sudden release from said die, air pressure means operative to open and close said clamping means, a solenoid valve to control said pressure means, an electric circuit including a limit switch to control the action of said valve, means travelling with said gripper means operative to engage said limit switch shortly prior to passage of the work through said die to cause closing of said clamping means and to engage said limit switch upon reciprocation of said gripper means toward said die to cause opening of said clamping means, and cam means automatically operative to open said clamping means when said gripper means approaches said die to seize and draw further work, should said pressure means have failed to open said clamping means.

'I. In drawing mechanism, a die through which work is drawn, gripper means operative to seize the work and draw suchwork through said die, clamping means located adjacent said die operative to frictionally grasp such work to prevent jumping of the latter end thereof upon sudden release from said die, fluid pressure means operative to open and close said clamping means, a solenoid valve to control said pressure means, and electric circuit including a limit switch to control the action oi said valve, means automatically operative to engage said limit switch to cause closing of said clamping means shortly prior to passage of the latter end of such work through said die, and cam means carried by said gripper means automatically operative to open said clamping means when said gripper means approaches said die to seize further work, should said fluid pressure means have failed to open said clamping means.

8. In tube drawing mechanism, a pair of iongitudinal guideways disposed parallel to one another, C-shaped frame members to one side of said guideways and supporting said guideways from above to permit lateral removal of work pieces from the outer sides of said guideways, dies at ends of said guideways, gripper means operable to travel along each of said guideways to draw work through said dies, and a set of tiltable rack members below each of said guideways whereon the work pieces are adapted to be deposited subsequent to the drawing operation, both sets of said rack members being inclinable to the side unobstructed by said frame members to discharge such work pieces.

9. In tube drawing mechanism, a pair of longitudinal guideways disposed parallel to one another, C-shaped frame members to one side of said guideways and supporting said guideways from above to permit lateral removal of work pieces from the outer sides of said guideways, dies at ends of said guideways, gripper means operable to travel along each of said guideways to draw work through said dies, a set of tiltable rack members below each of said guideways whereon the work pieces are adapted to be deposited subsequent to the drawing operation. and means operative to incline either of said sets of rack members, as desired, to the side unobstructed by said frame members to discharge such work pieces.

, 10. In drawing mechanism. a guideway, an endless chain having upper and lower courses substantially parallel thereto, means for driving said chain continuously in the same direction, and gripper means supported by said guideway for movement therealong and adapted to seize the work to be drawn, said gripper means comprising a carriage having trolley wheels by which said carriage is suspended from said guideway, jaws carried by said carriage, and means connecting said carriage to said chain and operative to open said jaws when such point of attachment to said chain is raised and to close said jaws when such point is lowered.

11. In drawing mechanism, a guideway, an end less chain disposed adjacent said guideway, means for driving said chain continuously in the same direction, and gripper means supported by said guideway for movement therealong and adapted to seize the work to be drawn, said gripper means comprising a carriage, paired jaw members slidably mounted in angularly related cam ways in said carriage, and lever means connecting said carriage to said chain and operative to open and close said gripper jaws as the point of attachment of said means passes from one course of said chain to the other.

12. In drawing mechanism, a guideway, an endless chain disposed adjacent said guideway, means I for driving said chain, and gripper means supported by said guideway for movement therealong and adapted to seize the work to be drawn, said gripper means comprising a carriage, paired jaw members slidably mounted in angularly related cam ways in said carriage, lever means pivotally mounted on said carriage. one end oi. said lever means being pivotally attached to said chain and the other end connected with said jaw members, and means operative to raise and lower said chain in its course of travel to open and close the gripper jaws.

13. In tube drawing mechanism, a pair of longitudinal guideways disposed parallel to one another, substantiall c-shaped frame members to one side of said guideways and supporting said guideways ufrom above to facilitate lateral removal of work pieces at the other side of said guideways, dies at ends of said guideways, sprockets adjacent each end of each of said guideways, endless chains mounted on said respective sprockets and comprising upper and lower courses substantially parallel to said respective guideways, means for driving said sprockets adjacent the ends of said guideways farthest removed from said dies, gripper means supported by each of said guideways for movement therealong, means con.- necting said gripper means to said respective chains operative to reciprocate said gripper means along said respective guideways upon movement of said chains in a single direction, said connecting means comprising lever means pivotally attached to said chains and operative to close said gripper means when the points of attachment of said lever means to said chains are on the lower courses of said chains and to open said gripper means when such points of attachment are raised above such lower courses, and means located adjacent said dies operative to grasp the work pieces shortly before such work pieces pass through said dies and support such work pieces to prevent whipping upon release from the die.

14. In drawing mechanism, a guideway, an endless chain supported adjacent said guideway and having upper and lower courses substantiall parallel thereto, means for driving said chain, gripper means supported by said guideway for reciprocating movement therealong, means including lever means connecting said gripper means to said chain operative to reciprocate said gripper means along said guideway upon movement of said endless chain in a single direction, said lever means being operative to maintain said gripper means in open ,position when the point of attachment of said lever means is travelling with one such course of said chain and to maintain said gripper means in closed position when such point of attachment is travelling with the other such course of said chain.

15. In drawing mechanism, a die through which work is drawn, gripper means operative to seize the work and draw such work through said die, clam-ping means located adjacent said die operative to frictionally grasp such work to prevent whipping of the latter end thereof upon sudden release from said die, means operative toclose said clamping means shortly prior to passage of the latter end of such work through said die, and cam means associated with said gripper means adapted to open said clamping means when said gripper means approaches said die to seize further work.

16. In drawing mechanism, a die through which work is drawn, gripper means operative to seize the Work and draw such work through said die, clamping means located adjacent said die operative to frictionally grasp such work to prevent whipping of the latter end thereof upon sudden release from said die, and cam means associated with said gripper means adapted to open said clamping means when said gripp m ns pproaches said die to seize further work.

17. In drawing mechanisn, thecombination of a guideway,.an endless chain supported adjacent said guideway and having a course substantially parallel thereto, means for driving said chain continuously in the same direction, a carriage supported by said guideway for reciprocating movement therealong, gripper means in said carriage, and means connecting said chain to said carriage, whereby the latter is reciprocated in opposite directions as the point of such connection passes from the one course to the other of said chain.

18. In drawing mechanism, the combination of a guideway, an endless chain supported adjacent said guideway and having a course substantially parallel thereto, means for driving said chain continuousl in the same direction, a carriage supported bysaid guideway for reciprocating movement therealong, gripper means in said carriage, means connecting said chain' to said carriage, whereby the latter is reciprocated in-.opposlte directions as the point of such connection passes from the one course to the other of said chain, and means adapted to operate said ripper means incidentally to movement of said carriage.

' 19. In drawing mechanism, the combination of a guideway, an endless chain supported adjacent said guideway and having a course substantially parallel thereto, means for driving said chain continuously in the same direction, a carriage supported by said guideway for reciprocating movement therealong, gripper means in said carriage, and means connecting said chain to'said carriage, whereby the latter is reciprocated in opposite directions as the point of such connection passes from the one course to the other of said chain, said connecting means being also operatively connected to said ripp r means.

20. In drawing mechanism, the combination of a guideway, an endless chain supported adiacent said guideway and having a course substantially parallel thereto, means for driving said chain continuously in the same direction, a carriage supported by said, guideway for reciprocating movement therealong, gripper means in said carriage, means connecting said chain to said carriage, whereby the latter is reciprocated in opposlte directions as the point of such connection passes from the one course to the other 01' said chain, said connecting means being also operatively connected to said gripper means, and independent means adapted to operate said gripper means.

21. In drawing mechanism, the combination of an approximately horizontal guideway, an endless chain supported adjacent said guideway in a substantially vertical plane and having upper and lower courses substantially parallel to said guideway, means for driving said chain continuously in the same direction, a carriage supported by said guideway for reciprocating movement therealong, gripper means on said carriage, and an arm attached at one end to said chain and at the other end to said carriage, whereby the latter is reciprocated in opposite directions as the point of attachment of. said arm to said chain passes from the one course thereof to the other.

22. In drawing mech'anism,th'e combination of a guideway, an endless chain supportedadjacent said guideway and having upper and lower courses substantially parallel thereto, means for driving said chain continuously in the same direction, a carriage supported by said guideway for reciprocating movement therealons. ripp means on said carriage, and an arm attached at one end to said chain and at the other end to said carriage, whereby the latter is reciprocated in opposite directions as the point of attachment of said arm to said chain passes from the one course thereof to the other, said arm being connected with said gripper means to operate the same incidentally to the swinging movement of said am thus produced.

23. In drawing mechanism, the combination of a guideway, an endless chain supported adjacent said guideway and having upper and lower courses substantially parallel thereto, means for driving said chain continuously in the same direction, a carriage supported by said guideway for reciprocating movement therealong, gripper means on said carriage, an arm attached at one end to said chain and at the other end to said carriage, whereby the latter is reciprocated in opposite directions as the point of attachment of said arm to said chain passes from the one course thereof to the other, and means adapted to operate said gripper means incidentally to'movement of said carriage.

24. In drawing mechanism, the combination of a guideway, an endless chain supported adjacent said guideway and having upper and lower courses substantially parallel thereto, means for driving said chain continuously in the same direction, a carriage supported by said guideway for reciprocating movement therealong, gripper means on said carriage, and sham attached at one end to said chain and at the other end to said carriage, whereby the latter is reciprocated in opposite directions as the point of attachment of said arm to said chain passes from the one course thereof to the other, said arm being connected with said gripper means to operate the same incidentally to the swinging movement of said arm thus produced, and independent means adapted to swing said arm to operate said gripper means.

25. In drawing mechanism, the combination of a guideway, an endless chain supported adjacent said guideway and having upper and lower courses substantially parallel thereto, means for driving said chain continuously in the same direction, a carriage supported by said guideway for reciprocating movement therealong, gripper means on said carriage, and a bell-crank lever pivotally mounted on said carriage, one arm of said lever being permanently pivotally attached to said chain so as to be carried by the latter through both of its courses and the other arm of said lever being operatively connected with said gripper means.

' 26. In drawing mechanism, the combination of a guideway, an endless chain supported adjacent said guideway and having upper and lower courses substantially parallel thereto, means for driving said chain continuously in the same direction, a carriage supported by said guideway for reciprocating movement therealong, paired gripper jaws on said carriage, and a bell-crank lever pivotally mounted on said carriage, one arm of said lever being permanently pivotally attached to said chain so as to be carried by the latter through both of its courses and the other arm of said lever having resilient connection with said gripper'jaws.

27. In drawing mechanism, the combination of a guideway, a chain supported in said guideway and having a course substantially parallel thereto, a carriage supported by said guideway for movement therealong, gripper means on said carriage, and an arm attached at one end to said chain and at the other to said carriage, said arm controlling said gripper means and the points of such attachment during the drawing operation being in line with such course of the chain.

28. In drawing mechanism, the combination oi a guideway, a chain supported in said guideway and having a course substantially parallel thereto, a carriage supported in underslung relation to said guideway for reciprocating movement therealong, gripper means on said carriage, and an arm attached at one end to said chain and at the other to said carriage, said am controlling said gripper means and the points of such attachment during the drawing operation being in line with such course of the chain.

29. In drawing m ech anis m, paired draw benches positioned in parallel, dies located at adjacent ends of said benches, work gripping means on said respective benches mounted for reciprocable movement therealong, endless chains for moving said grippin means respectively, and 

